Repair of UVA-induced elastic fiber and collagen damage by 0.05% retinaldehyde cream in an ex vivo human skin model

Background: Cellular effects of UV exposure are implicated in cutaneous agi ng. UV radiations induce structural and cellular changes in all the compart ments of skin, Aim: To study the antiaging efficacy of a cream containing 0 .05% retinaldehyde with an ex vivo technique using human skin in order to a pproximate in vivo metabolic conditions, Methods: Human skin explants were maintained alive in organ culture for 18 days and subjected to UVA exposure , thus simulating skin photoaging. Retinaldehyde cream was then applied to the surface of the epidermis for 2 weeks and the results were compared with those of nontreated skin explants. Dermal repair was analyzed histological ly with quantification of collagen and elastic fibers, and biochemically by the measure of newly synthesized collagen as shown by adding tritiated pro line to the culture medium. Results: UVA exposure induced significant alter ations of collagen and elastic fibers as shown by morphometric analysis. In all UVA-exposed and then retinaldehyde-treated skin specimens, collagen an d elastic fibers were restored to the level of nonexposed skin. UVA exposur e induced a decrease in collagen synthesis, whereas in retinaldehyde-treate d UVA-exposed skin the synthesis was similar to that of unexposed skin. Con clusion: It has been shown that retinaldehyde has many of the properties of tretinoin in its biological and beneficial effects on photoaging. We have verified some of these previous observations, especially on dermal connecti ve tissue, by obtaining significant repair of elastic fibers and collagen a lteration induced by UVA exposure.